After searching a lot, I found the following solution which is working in my cases:
.opacity_30{
background:rgb(255,255,255); /* Fallback for web browsers that don't support neither RGBa nor filter */
background: transparent\9; /* Backslash 9 hack to prevent IE 8 from falling into the fallback */
background:rgba(255,255,255,0.3); /* RGBa declaration for modern browsers */
-ms-filter:progid:DXImageTransform.Microsoft.gradient(startColorstr=#4CFFFFFF,endColorstr=#4CFFFFFF); /* IE 8 suppoerted; Sometimes Hover issues may occur, then we can use transparent repeating background image :( */
filter:progid:DXImageTransform.Microsoft.gradient(startColorstr=#4CFFFFFF,endColorstr=#4CFFFFFF); /* needed for IE 6-7 */
zoom: 1; /* Hack needed for IE 6-8 */
}
/* To avoid IE more recent versions to apply opacity twice (once with rgba and once with filter), we need the following CSS3 selector hack (not supported by IE 6-8) */
.opacity_30:nth-child(n) {
filter: none;
}
*Important: To calculate ARGB(for IEs) from RGBA, we can use online tools: